Foreign fish invading Great Lakes
In 1990, a new fish species called the round goby entered Lake Erie, carried from the Black or Caspian Seas inside the ballast tanks of a ship. Now, Sigal Balshine of McMaster University has found that the round goby has become abundant throughout the Great Lakes basin. She says the gobies are very aggressive, which allows them to take over the territory of native fish species, such as logperch. They also reproduce in large numbers and feed on the eggs and fry of native fish. Scientists believe gobies have already driven some native fish species extinct.
-M.G.
Source: Journal of Great Lakes Research
Canada’s polar ice thinning
Although ice caps and glaciers cover only 150,000 square kilometres in the Canadian Arctic-Greenland has ten times the ice cover-their melting would significantly contribute to global sea level rise, according to Waleed Abdalati, a researcher at NASA’s Goddard Space Flight Center. He says it’s because ice-covered polar regions are especially sensitive to climate change. Records show that temperatures and snow accumulation both increased in the Canadian Arctic between 1995-2000, compared to the period 1951-1980. Abdalati measured the thickness of ice caps on Baffin and Ellesmere Islands in 1995 and again in 2000. Though some glaciers have thickened, significant thinning has occurred at the lower altitudes where glaciers melt.
-M.G.
Source: NASA
